Dentofacial growth

ORIGINAL ARTICLE

Dentofacial growth changes in subjects with untreated Class II malocclusion from late puberty through young adulthood
Tiziano Baccetti,a Franka Stahl,b and James A. McNamara, Jrc Florence, Italy, Rostock, Germany, and Ann Arbor, Mich Introduction: The purpose of this longitudinal study was to compare dentofacial growth changes in untreated subjects with Class II Division 1malocclusion with those in subjects with normal (Class I) occlusion from late puberty through young adulthood. Methods: The Class II Division 1 sample consisted of 23 subjects (10 male, 13 female). The Class I sample included 30 subjects (13 male, 17 female). The lateral cephalograms of the subjects in both groups were analyzed at 2 consecutive stages of development: T1, postpubertal observation(cervical vertebral maturation stage 6), and T2, young adulthood stage. The average time between T1 and T2 was 3.5 years. The statistical comparisons of the growth changes in the 2 groups were performed with Mann-Whitney U tests. Results: From late puberty through young adulthood, dentofacial growth in subjects with untreated Class II malocclusion does not show significant differences when comparedwith that observed in untreated subjects with normal occlusion. Conclusions: These findings show that Class II dentoskeletal disharmony does not exhibit significant growth change from late puberty through young adulthood. (Am J Orthod Dentofacial Orthop 2009;135:148-54)

he literature contains evidence that subjects with various dentoskeletal disharmonies (eg, Class II or Class III dentoskeletalrelationships) grow differently from subjects with normal dentoskeletal relationships in both the amount and the direction of growth of the craniofacial structures.1-8 With regard to Class II Division 1 malocclusion, several longitudinal studies have demonstrated a significant deficiency in the amount of mandibular growth in untreated Class II subjects with mandibular retrusion when compared withuntreated Class I subjects at the circumpubertal period.1,4,5 These data have offered valid assistance in
a Associate professor, Department of Orthodontics, University of Florence, Florence, Italy; Thomas M. Graber Visiting Scholar, Department of Orthodontics and Pediatric Dentistry, School of Dentistry, University of Michigan, Ann Arbor. b Research associate, Department of Orthodontics, University ofRostock, Rostock, Germany; postdoctoral scholar, Department of Orthodontics and Pediatric Dentistry, School of Dentistry, University of Michigan, Ann Arbor. c Thomas M. and Doris Graber Endowed Professor of Dentistry, Department of Orthodontics and Pediatric Dentistry, School of Dentistry; professor of Cell and Developmental Biology, School of Medicine; research professor, Center for Human Growthand Development, University of Michigan; private practice, Ann Arbor, Mich. Supported by the Max-Kade Foundation and the German Society of Orthodontics, with additional support from the Thomas M. and Doris Graber Endowed Professorship by the University of Michigan. Reprint requests to: Tiziano Baccetti, Università degli Studi di Firenze, Via del Ponte di Mezzo, 46-48, 50127, Firenze, Italy;e-mail, t.baccetti@odonto. unifi.it. Submitted, January 2007; revised and accepted, March 2007. 0889-5406/$36.00 Copyright © 2009 by the American Association of Orthodontists. doi:10.1016/j.ajodo.2007.03.033

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planning treatment for patients with Class II malocclusion and in understanding growth expectations in untreated subjects with this type of disharmony. The growth differences between ClassII and Class I subjects also have pointed to the appropriateness of using subjects with untreated Class II malocclusions as controls in studies on the effectiveness of Class II treatment around puberty.9 Longitudinal investigations on craniofacial growth in patients with untreated Class II malocclusion so far have focused on prepubertal and pubertal changes.1-5,10 However, information on...